Expand VLR tests

Print the IMSI used for each test. This enables expansion to tests with
several IMSIs in follow-up patches.

Change-Id: I7958608e5136351f7b7c0c57fe79791d989ce9c3
Related: OS#2864
diff --git a/tests/msc_vlr/msc_vlr_test_call.ok b/tests/msc_vlr/msc_vlr_test_call.ok
index a965a70..1861dfc 100644
--- a/tests/msc_vlr/msc_vlr_test_call.ok
+++ b/tests/msc_vlr/msc_vlr_test_call.ok
@@ -1 +1,2 @@
+Testing for IMSI 901700000004620
 Done